As a liquid crystal display apparatus, referred to below as LCD, is coming into widespread use, the demand for a polarizing plate is increasing rapidly. In general, a polarizing plate film includes a polarizing layer, exhibiting a light polarizing capability, and a protective film(s) bonded to one or both surfaces thereof (see FIG. 14(B)). As the material for the polarizing layer, polyvinyl alcohol, referred to below as PVA, is predominantly used. A polarizing film for a polarizing layer is formed by uniaxially stretching a PVA film, dyeing the resulting polarizing film with iodine or a dichroic dye and cross-linking with a boron compound. The sequence of the uniaxial stretching and the dyeing may be inverted, if so desired. As the protective film, mainly cellulose triacetate, referred to below as TAC, optically transparent and exhibiting only low birefringence, is predominantly used. The polarizing plate is usually stretched in the longitudinal direction, so that the axis of light absorption of the polarizing film is approximately parallel to the longitudinal direction (see FIG. 14(A)). The polarizing plate film is provided with an adhesive layer for bonding to the substrate. To the adhesive layer is bonded a release film for protecting the adhesive layer from contaminants, such as dust and dirt. The polarizing plate film, having the release film bonded thereto, is furnished to the market, with a strip-shaped film, stretched in the longitudinal direction, in a roll form.
In a conventional LCD employing the TN (twisted nematic) liquid crystal, the polarizing plate is arranged with its axis of light transmission inclined 45° relative to the longitudinal or transverse direction of an image frame. Thus, such a method consisting in bonding pieces of the polarizing plate, obtained on pre-punching a roll of a polarizing plate in a direction of 45° relative to the longitudinal direction of the roll, one by one to an LCD (see for example JP Patent Kokai JP-A-2002-23151) or such a method consisting in bonding a polarizing plate of a roll form to an LCD image surface as the longitudinal or transverse direction of the LCD image surface is inclined at an angle of 45° relatove to the longitudinal direction of the roll and subsequently severing the polarizing plate (see for example JP Patent Kokai JP-A-11-95028, FIG. 14(A) have been devised. In an LCD employing a VA (vertical alignment) liquid crystal an LCD employing an IPS (in-plane switching) liquid crystal, the axis of light transmission of the polarizing plate is arranged in the longitudinal or transverse direction of the image frame and pieces of the polarizing plate are bonded one by one on the LCD.
In a conventional LCD, employing the TN (twisted nematic) crystal, such a substrate on both sides of which have been bonded polarizing plates is used. Specifically, a first polarizing plate, having the axis of light transmission inclined 45° relative to the longitudinal or transverse direction of the image frame, is arranged on one surface of the substrate, whilst a second polarizing plate, having the axis of light transmission inclined 90° relative to the axis of transmission of the first polarizing plate, is arranged on the opposite surface thereof.